A video of a U.S. military warning broadcast posted by U.S. President Donald Trump on Truth Social on the 15th (local time). Truth Social screengrab

The U.S. military posted to social media a video broadcasting a warning that it will respond with force if there is no cooperation with the maritime blockade against Iran.

In the 26-second video that U.S. Central Command posted to X on the 15th (local time), it says, “The United States has declared an official blockade of Iranian coastal ports, and this is a lawful act,” advising vessels entering or leaving Iranian ports to turn back and cease navigation.

It then warns, “Do not attempt to break the blockade. If you do not comply with the blockade, we will use force,” and, “The U.S. Navy is prepared to enforce compliance.” It also says there will be boarding inspections for searches and seizures of vessels traveling to and from Iranian ports, instructing them to alter course and prepare for boarding. Central Command added that, in line with the implementation of the maritime blockade against Iran, U.S. Navy ships are patrolling the Gulf of Oman.

Fox News explained that the warning broadcast originates from U.S. Navy ships assigned to the blockade mission.

U.S. President Donald Trump also reposted the video on the social-media platform Truth Social. It appears intended to signal a determination to enforce a blockade of the Strait of Hormuz and pressure Iran to reach a deal.